Hi Chris,
Make magazine have some good tutorials on Arduino, start here
http://blog.makezine.com/arduino/
I'd recommend getting a board (if you haven't already) and just having a play. Most places that sell Arduino also sell starter kits with a breadboard, jumper leads and a selection of interesting components to get you started.
What are you planning on building? I have a half finished Arduino weather station that I might finish one day ....
Malc